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endogamy en·dog·a·my (ěn-dŏg'ə-mē)
Reproduction by the fusion of gametes of similar ancestry.
Marriage within a particular group in accordance with custom or law.
custom enjoining one to marry within one's own group. The penalties for transgressing endogamous restrictions have varied greatly among cultures and have ranged from death to mild disapproval. When marriage to an outside group is mandated, it is referred to as exogamy.